WO2016035311A1 - Wavelength conversion filter and solar cell module using same - Google Patents

Wavelength conversion filter and solar cell module using same Download PDF

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Publication number
WO2016035311A1
WO2016035311A1 PCT/JP2015/004395 JP2015004395W WO2016035311A1 WO 2016035311 A1 WO2016035311 A1 WO 2016035311A1 JP 2015004395 W JP2015004395 W JP 2015004395W WO 2016035311 A1 WO2016035311 A1 WO 2016035311A1
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Prior art keywords
wavelength
light
phosphor
scattering material
transparent resin
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PCT/JP2015/004395
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French (fr)
Japanese (ja)
Inventor
善光 生駒
真治 柴本
崇志 岡田
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パナソニックＩｐマネジメント株式会社
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Priority to JP2016546312A priority Critical patent/JP6358548B2/en
Publication of WO2016035311A1 publication Critical patent/WO2016035311A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/042—PV modules or arrays of single PV cells
    • H01L31/048—Encapsulation of modules
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
    • H01L31/054—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means
    • H01L31/055—Optical elements directly associated or integrated with the PV cell, e.g. light-reflecting means or light-concentrating means where light is absorbed and re-emitted at a different wavelength by the optical element directly associated or integrated with the PV cell, e.g. by using luminescent material, fluorescent concentrators or up-conversion arrangements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/52—PV systems with concentrators

Definitions

  • the present invention relates to a wavelength conversion technique, and more particularly to a wavelength conversion filter that converts a wavelength of light having an excitation wavelength and a solar cell module using the same.
  • Solar cells for converting sunlight into electrical energy are clean renewable energy, but in general, only light of some wavelengths of sunlight is used for photoelectric conversion, which is the photoelectric conversion efficiency. It is a factor of decline. Therefore, a wavelength conversion layer that converts light having a wavelength that cannot be used in the solar cell into light having a usable wavelength is provided.
  • phosphor particles having an average particle diameter of 100 nm are used in order to reduce scattering on the surface of the phosphor particles (see, for example, Patent Document 1).
  • the present invention has been made in view of such circumstances, and an object thereof is to provide a technique for suppressing a decrease in transmittance while converting light having an unusable wavelength into light having a usable wavelength. It is in.
  • a wavelength conversion filter includes a transparent resin, a phosphor mixed with the transparent resin, and a fluorescent resin mixed with the transparent resin.
  • This solar cell module is a solar cell module in which a protective member, a sealing member, and solar cells are stacked, and the sealing member is mixed with a transparent resin, a phosphor mixed with the transparent resin, and the transparent resin. And a scattering material that scatters light having an excitation wavelength of the phosphor rather than light having an emission wavelength of the phosphor.
  • the present invention it is possible to suppress a decrease in transmittance while converting light having an unusable wavelength into light having a usable wavelength.
  • FIG. 5A and 5B are diagrams showing the scattering intensity distribution and the scattering intensity distribution in which the component in the straight direction is normalized to 1 when the particle diameter of the scattering material in FIG. 3 is 100 nm.
  • 6A and 6B are diagrams showing the scattering intensity distribution and the scattering intensity distribution in which the component in the straight direction is normalized to 1 when the particle size of the scattering material in FIG. 3 is 300 nm.
  • FIGS. 8A and 8B are diagrams showing the scattering intensity distribution when the particle size of the scattering material of FIG. It is a figure which shows the wavelength dependence of the transmittance
  • the Example of this invention is related with the solar cell module provided with the photovoltaic cell.
  • photoelectric conversion efficiency is lower for light in the low wavelength region of ultraviolet light and visible light than in light in other wavelength regions of visible light.
  • a phosphor is mixed in the sealing member of the solar battery cell, and the phosphor is in response to light in the low wavelength region of ultraviolet light and visible light. To convert the wavelength.
  • the particle size of phosphors has been set to several tens of nm in order to suppress a decrease in transmittance of the sealing member.
  • the phosphor has a larger particle size, and should be, for example, several ⁇ m.
  • the transmittance of the sealing member is decreased, so that visible light is reflected and the photoelectric conversion efficiency of the solar battery cell is decreased.
  • the purpose of this example is to suppress a decrease in transmittance for light having a high photoelectric conversion efficiency in a solar battery cell while improving the wavelength conversion efficiency by increasing the particle size of the phosphor. .
  • FIG. 1 is a cross-sectional view showing a configuration of a solar cell module 100 according to an embodiment of the present invention.
  • the solar cell module 100 includes a solar cell 10, a first tab wire 16 a collectively referred to as a tab wire 16, a second tab wire 16 b, a first sealing member 18 a collectively referred to as a sealing member 18, and a second sealing member. 18b, the 1st protection member 20a and the 2nd protection member 20b which are named the protection member 20 generically.
  • the solar battery cell 10 absorbs incident light and generates a photovoltaic power, and is formed of a semiconductor material such as crystalline silicon, gallium arsenide (GaAs), or indium phosphorus (InP).
  • the structure of the solar battery cell 10 is not particularly limited, but here, as an example, it is assumed that crystalline silicon and amorphous silicon are stacked.
  • the solar battery cell 10 has a light receiving surface 12 that is one of the surfaces of the solar battery cell 10 and a back surface 14 facing away from the light receiving surface 12.
  • the light receiving surface 12 means a main surface on which solar light is mainly incident in the solar battery cell 10, and specifically, a surface on which most of the light incident on the solar battery cell 10 is incident. It is. Further, electrodes (not shown) are provided on the light receiving surface 12 and the back surface 14.
  • FIG. 2 shows the wavelength dependence of the external quantum efficiency of the solar battery cell 10.
  • the horizontal axis indicates the wavelength
  • the vertical axis indicates the external quantum efficiency of the solar battery cell 10.
  • the external quantum efficiency is the ratio of the number of electrons output from the solar cell 10 to the number of photons incident on the solar cell 10, and the higher the external quantum efficiency, the higher the photoelectric conversion efficiency. It can be said.
  • the external quantum efficiency shows a substantially constant high value. It can be said that such a wavelength is higher than that of visible green light.
  • the external quantum efficiency decreases as the wavelength becomes shorter.
  • the slope of the external quantum efficiency with respect to the wavelength becomes steeper at the wavelength of 450 nm or less than the wavelength of 500 nm to 450 nm.
  • the former wavelength corresponds to the wavelength of visible blue light
  • the latter wavelength corresponds to violet light and ultraviolet light of visible light.
  • the tab wire 16 is adhered on the light receiving surface 12 and the back surface 14 so as to be electrically connected to an electrode (not shown).
  • the tab wire 16 and the electrode may be connected via a resin layer.
  • the tab line 16 extends in the horizontal direction of FIG. 1 where a plurality of solar cells 10 are arranged, and the electrode on the light receiving surface 12 side of one adjacent solar cell 10 and the other solar cell 10 (not shown). ) On the back surface 14 side.
  • the first protective member 20a is provided on the light receiving surface 12 side of the solar battery cell 10, and protects the solar battery cell 10 from the external environment and transmits light to be absorbed by the solar battery cell 10.
  • the first protection member 20a is, for example, a glass substrate.
  • the first protective member 20a may be polycarbonate, acrylic, polyester, or fluorinated polyethylene in addition to the glass substrate.
  • the second protective member 20 b is a back sheet provided on the back surface 14 side of the solar battery cell 10.
  • the second protective member 20b may be the same glass as the first protective member 20a or a transparent substrate such as plastic.
  • the first protection is achieved.
  • the light reaching the second protective member 20b from the member 20a may be reflected in the direction of the solar battery cell 10.
  • the sealing member 18 is provided between the first protection member 20a and the light receiving surface 12, and between the second protection member 20b and the back surface 14, respectively, and prevents moisture from entering the solar cells 10 and the like. It is a protective material that improves the overall strength of the battery module 100.
  • the 1st protection member 20a, the 1st sealing member 18a, the photovoltaic cell 10, the 2nd sealing member 18b, and the 2nd back sheet 22b are laminated
  • the sealing member 18 also has a function as a wavelength conversion filter.
  • the configuration of the sealing member 18 will be described in more detail.
  • FIG. 3 shows the configuration of the sealing member 18.
  • the sealing member 18 includes a phosphor 30, a scattering material 32, and a transparent resin 34.
  • the transparent resin 34 has transparency that can sufficiently transmit sunlight.
  • the transparent resin 34 is a resin material such as ethylene vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), polyimide, polyethylene, polypropylene, polyethylene terephthalate (PET).
  • EVA ethylene vinyl acetate copolymer
  • PVB polyvinyl butyral
  • PET polyethylene terephthalate
  • the phosphor 30 is mixed in the transparent resin 34 and converts the wavelength of light having a part of the wavelength contained in sunlight. As described above, in order to improve the photoelectric conversion efficiency of the solar battery cell 10, the phosphor 30 absorbs light in a short wavelength region where the photoelectric conversion efficiency in the solar battery cell 10 is low, and the long wavelength with high photoelectric conversion efficiency. The light of the region is emitted. More specifically, the phosphor 30 converts the wavelength of ultraviolet light to blue light of 500 nm or less from green light to near infrared light of 500 nm to 1100 nm. In particular, the phosphor 30 is efficiently excited at 300 nm or more where the sunlight spectrum intensity is relatively large. In addition, an inorganic phosphor is used for the phosphor 30 from the viewpoint of durability and moisture resistance.
  • the particle size of the phosphor 30 is several ⁇ m, the wavelength conversion efficiency is improved, but the transmittance is lowered.
  • the transmittance is reduced, reflection by the phosphor 30 generates a component of light that is reflected toward the side on which sunlight is incident without going to the solar battery cell 10.
  • the photoelectric conversion efficiency of the solar battery cell 10 is lowered.
  • the particle size of the phosphor 30 is set to several ⁇ m, and the scattering material 32 is also mixed with the transparent resin 34 in order to suppress a decrease in transmittance of 500 nm or more.
  • the scattering material 32 will be described later.
  • the particle diameters of the plurality of phosphors 30 may not be uniform, and in that case, the average particle diameter may be several ⁇ m. Since a known technique may be used for the measurement of the average particle diameter, description thereof is omitted here.
  • FIG. 4 shows an excitation spectrum and an emission spectrum of (Ba, Sr) 2 SiO 4 : Eu that is the phosphor 30.
  • the horizontal axis indicates the wavelength, and the vertical axis indicates the intensity (arbitrary unit).
  • an excitation spectrum 40 and an emission spectrum 42 are shown.
  • the excitation spectrum 40 shows a change in wavelength of the intensity of light absorbed by the phosphor 30.
  • the excitation peak P1 is the maximum intensity in the excitation spectrum 40, and the wavelength thereof is about 300 nm.
  • the excitation wavelength region 44 has a wavelength width that has an intensity that is equal to or greater than half the intensity of the excitation peak P1, and this corresponds to a half-value width with respect to the intensity of the excitation peak P1.
  • the excitation wavelength region 44 may be specified by a value different from the half value of the intensity of the excitation peak P1.
  • the excitation wavelength region 44 in FIG. 4 is defined from about 260 nm to about 490 nm.
  • the wavelength of light excited by the phosphor 30 is collectively referred to as “excitation wavelength”. Therefore, the entire excitation spectrum 40 may be specified by the excitation wavelength, a part of the excitation spectrum 40 such as the excitation wavelength region 44 may be specified, and one point in the excitation spectrum 40 such as the excitation peak P1. May be specified.
  • the emission spectrum 42 shows the wavelength change of the intensity of the light emitted from the phosphor 30.
  • the emission peak Q1 is the maximum intensity in the emission spectrum 42, and its wavelength is 540 nm.
  • the emission wavelength region 46 is defined in the same manner as the excitation wavelength region 44 with respect to the emission peak Q1.
  • the emission wavelength region 46 in FIG. 4 is defined from about 510 nm to about 570 nm.
  • the wavelength of light emitted from the phosphor 30 is collectively referred to as “emission wavelength”. Therefore, the entire emission spectrum 42 may be specified by the emission wavelength, a part of the emission spectrum 42 such as the emission wavelength region 46 may be specified, and one point in the emission spectrum 42 such as the emission peak Q1. May be specified.
  • the scattering material 32 has a grain shape.
  • the scattering material 32 scatters light while having wavelength selectivity.
  • the scattering material 32 is, for example, silicon dioxide (SiO 2 ), which is also called silica or silicic anhydride.
  • the scattering material 32 is, for example, zirconium oxide (IV) (ZrO 2 ), which is also called zirconia.
  • IV zirconium oxide
  • the scattering material 32 is SiO 2 .
  • the wavelength selectivity required for the scattering material 32 is indicated by the following two characteristics.
  • the first characteristic is that the transmittance is low at the excitation wavelength of the phosphor 30, for example, at the excitation peak P ⁇ b> 1 or the excitation wavelength region 44. This corresponds to scattering light having a wavelength of 500 nm or less when the phosphor 30 is (Ba, Sr) 2 SiO 4 : Eu. By reducing the transmittance, light of that wavelength is scattered by the scattering material 32 and is easily absorbed by the phosphor 30.
  • the second characteristic is that the transmittance is high at the emission wavelength of the phosphor 30, for example, at the emission peak Q 1 or the emission wavelength region 46.
  • the scattering material 32 scatters light having an excitation wavelength of the phosphor 30 rather than light having an emission wavelength of the phosphor 30.
  • FIGS. 5A and 5B show the scattering intensity distribution when the particle size of the scattering material 32 is 100 nm and the scattering intensity distribution in which the straight direction component is normalized to 1.
  • FIG. FIG. 5A shows the scattered intensity distribution
  • FIG. 5B shows the normalized scattered intensity distribution. These are measured in a state where SiO 2 is contained in EVA.
  • the wavelength of the light to irradiate is 350 nm, 550 nm, and 1000 nm. 350 nm is included in the excitation wavelength region 44, 550 nm is included in the emission wavelength region 46, and 1000 nm is a wavelength longer than the emission wavelength.
  • the direction dependency of the scattering intensity is low.
  • the scattering intensity at the wavelength 350 nm result 90 is the largest, the scattering intensity at the wavelength 550 nm result 92 is the next largest, and the scattering intensity at the wavelength 1000 nm result 94 is the smallest. That is, the shorter the wavelength, the greater the scattering intensity.
  • the directivity of the wavelength 350 nm result 90 is larger than the directivity of the wavelength 550 nm result 92, and the directivity of the wavelength 550 nm result 92 is larger than the directivity of the wavelength 1000 nm result 94. That is, the directivity increases as the wavelength becomes shorter. As the directivity increases, the tendency of only forward scattering increases, and when the directivity decreases, the backscatter increases.
  • FIG. 6 (a)-(b) show the scattering intensity distribution when the particle size of the scattering material 32 is 300 nm and the scattering intensity distribution in which the component in the straight direction is normalized to 1.
  • FIG. 6 (a)-(b) are shown similarly to FIGS. 5 (a)-(b). Comparing FIG. 6A and FIG. 5A, the scattering intensity is larger when the particle size of the scattering material 32 is 300 nm than when the particle size of the scattering material 32 is 100 nm. ing. Further, when FIG. 6B and FIG. 5B are compared, the wavelength-oriented direction is more when the particle size of the scattering material 32 is 300 nm than when the particle size of the scattering material 32 is 100 nm. The difference in sex is getting smaller.
  • FIG. 7 (a)-(b) show the scattering intensity distribution when the particle size of the scattering material 32 is 500 nm and the scattering intensity distribution in which the straight direction component is normalized to 1.
  • FIG. 7 (a)-(b) are also shown in the same manner as FIGS. 5 (a)-(b).
  • the scattering intensity is larger than in FIG. 6A
  • the difference in directivity depending on the wavelength is smaller than in FIG. 6B.
  • FIGS. 8A to 8B show the scattering intensity distribution when the particle diameter of the scattering material 32 is 1000 nm and the scattering intensity distribution in which the straight direction component is normalized to 1.
  • FIG. 8 (a)-(b) are also shown in the same manner as FIGS. 5 (a)-(b).
  • FIG. 8A when the particle size of the scattering material 32 is 1000 nm, the scattering intensity is maximized in this simulation.
  • FIG. 8B when the particle size of the scattering material 32 is 1000 nm, the difference in directivity due to the wavelength is minimized among the measurements made this time. From FIG. 5 (a)-(b), FIG. 6 (a)-(b), FIG. 7 (a)-(b), and FIG.
  • FIG. 9 shows the wavelength dependence of the transmittance of the sealing member 18 in which the scattering material 32 is dispersed.
  • the horizontal axis indicates the wavelength
  • the vertical axis indicates the transmittance.
  • the change in transmittance is small in all measured wavelengths, particularly in the excitation wavelength region 44 and the emission wavelength region 46.
  • the transmittance in the excitation wavelength region 44 is lower than the transmittance in the emission wavelength region 46.
  • the 100 nm scattering material 50 and the 300 nm scattering material 52 have the above-described two characteristics, and the 1000 nm scattering material 54 does not have characteristics with respect to the above-described two characteristics.
  • the 500 nm scattering material has the above-described two characteristics. Therefore, in consideration of these, the average particle diameter of the scattering material 32 should be 500 nm or less.
  • FIG. 10 shows the blending conditions of the sealing member 18.
  • four kinds of blending conditions are shown, two of which are the first pattern and the second pattern corresponding to the example, and the remaining two are the first comparative example and the second pattern for comparison with the example. It is a comparative example.
  • the conditions for the phosphor 30 and the transparent resin 34 are common, and the conditions for the scattering material 32 are all different.
  • the composition of the phosphor 30 is (Ba, Sr) 2 SiO 4 : Eu, the addition amount is 1.0% by volume, and the particle size is 16000 nm.
  • the composition of the transparent resin 34 is EVA, and the refractive index thereof is 1.48.
  • the composition of the scattering material 32 in the first pattern, the second pattern, and the second comparative example is SiO 2 and its refractive index is 1.44.
  • the amount of SiO 2 added in the first pattern is 5.0% by volume and the particle size is 100 nm
  • the amount of SiO 2 added in the second pattern is 8.0% by volume
  • the particle size is 300 nm.
  • the amount of SiO 2 added in the second comparative example is 10.0% by volume, and the particle size is 1000 nm. These correspond to the three particle sizes already compared.
  • the scattering material 32 is not mixed in the first comparative example.
  • FIG. 11 shows the wavelength dependence of the transmittance for each of the aforementioned blending conditions.
  • the horizontal axis indicates the wavelength
  • the vertical axis indicates the transmittance. Since the scattering material 32 is not mixed in the first comparative example 64, the transmittance is high over all the measured wavelengths. Therefore, the amount of light absorbed by the phosphor 30 in the excitation wavelength region 44 is reduced, and the amount of light wavelength-converted by the phosphor 30 is also reduced. As a result, there is little improvement in photoelectric conversion efficiency by the solar battery cell 10.
  • the second comparative example 66 since the scattering material 32 having no wavelength selectivity is mixed, the transmittance is low over all measured wavelengths. In particular, since the transmittance at the emission wavelength region 46 and above is reduced, the photoelectric effect by the solar battery cell 10 is also reduced.
  • the transmittance of the first pattern 60 and the second pattern 62 is reduced in the excitation wavelength region 44 as in the second comparative example 66. Therefore, the amount of light absorbed by the phosphor 30 in the excitation wavelength region 44 increases, and the amount of light that is wavelength-converted by the phosphor 30 also increases. Further, in the first pattern 60 and the second pattern 62, the transmittance is less reduced in the light emission wavelength region 46 and in the wavelength longer than that in the first comparative example 64. As a result, the photoelectric conversion efficiency by the solar battery cell 10 is improved.
  • the scattering material 32 may be made of ZrO 2 instead of SiO 2 . It is possible to mix ZrO 2 as the scattering material 32 with respect to the phosphor 30 and the transparent resin 34 under the blending conditions of FIG.
  • the refractive index of ZrO 2 is 2.2, for example, the addition amount is 0.005% by volume, and the particle size is 150 nm.
  • the difference in refractive index between SiO 2 and EVA is “0.04”, and the difference in refractive index between ZrO 2 and EVA is “1.04”. The latter has a larger difference in refractive index than the former. The greater the difference in refractive index, the easier it is for light to scatter.
  • the addition amount of the scattering material 32 is determined according to the difference between the refractive index of the scattering material 32 and the refractive index of the transparent resin 34. Specifically, the addition amount is increased as the difference is smaller.
  • the solar battery cell is improved while improving the wavelength conversion efficiency. 10 can suppress a decrease in transmittance with respect to light having a wavelength that is efficiently photoelectrically converted. Moreover, since the fall of the transmittance
  • the scattering material 32 having an average particle size of 500 nm or less since the scattering material 32 having an average particle size of 500 nm or less is used, light having a wavelength of 500 nm or less can be scattered. Moreover, since the addition amount of the scattering material 32 is increased as the difference between the refractive index of the scattering material 32 and the refractive index of the transparent resin 34 is smaller, an amount of the scattering material 32 suitable for having wavelength selectivity can be mixed. .
  • the wavelength conversion filter 18 includes a transparent resin 34, a phosphor 30 mixed with the transparent resin 34, and a phosphor 30 mixed with the transparent resin 34, rather than light having an emission wavelength of the phosphor 30. And a scattering material 32 that scatters light of the excitation wavelength.
  • the scattering material 32 may scatter light having a wavelength of 500 nm or less.
  • the scattering material 32 has a grain shape, and the average particle diameter may be 500 nm or less.
  • the addition amount of the scattering material 32 may be increased as the difference between the refractive index of the scattering material 32 and the refractive index of the transparent resin 34 is smaller.
  • This solar cell module 100 is a solar cell module 100 in which a protective member 20, a sealing member 18, and solar cells 10 are stacked.
  • the sealing member 18 is mixed with a transparent resin 34 and a transparent resin 34. It includes a phosphor 30 and a scattering material 32 that is mixed in the transparent resin 34 and scatters light having an excitation wavelength of the phosphor 30 rather than light having an emission wavelength of the phosphor 30.
  • the wavelength conversion filter in which the phosphor 30 and the scattering material 32 are mixed with the transparent resin 34 is configured as the sealing member 18.
  • the wavelength conversion filter may be provided separately from the sealing member 18. If demonstrating it concretely, the wavelength conversion filter may be arrange
  • the wavelength conversion filter may be disposed between the back surface 14 of the solar battery cell 10 and the second sealing member 18b.
  • the wavelength conversion filter may be attached to the light receiving side of the first protective member 20a.
  • the wavelength conversion filter may be disposed between the first protective member 20a and the first sealing member 18a.
  • the wavelength conversion filter may be disposed between the second protective member 20b and the second sealing member 18b. According to this modification, the degree of freedom of configuration can be improved.
  • the present invention it is possible to suppress a decrease in transmittance while converting light having an unusable wavelength into light having a usable wavelength.

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  • Condensed Matter Physics & Semiconductors (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

As a wavelength conversion filter, a sealing member 18 includes a transparent resin 34 having transparency capable of adequately transmitting sunlight. A fluorescent body 30 is mixed in with the transparent resin 34, absorbs light of an excitation wavelength in sunlight, and outputs light of an emission wavelength. A light scattering material 32 is also mixed in with the transparent resin 34 and scatters light of the excitation wavelength of the fluorescent body 30 more than the light of the emission wavelength of the fluorescent body 30.

Description

波長変換フィルタおよびそれを利用した太陽電池モジュールWavelength conversion filter and solar cell module using the same
　本発明は、波長変換技術に関し、特に励起波長の光に対して波長を変換する波長変換フィルタおよびそれを利用した太陽電池モジュールに関する。 The present invention relates to a wavelength conversion technique, and more particularly to a wavelength conversion filter that converts a wavelength of light having an excitation wavelength and a solar cell module using the same.
　太陽光を電気エネルギーに変換するための太陽電池は、クリーンな再生可能エネルギーであるが、一般的に、太陽光のうちの一部の波長の光しか光電変換に利用されず、これが光電変換効率低下の要因になっている。そのため、太陽電池において利用不可能な波長の光を利用可能な波長の光へ変換させる波長変換層が設けられる。波長変換層には、蛍光体微粒子表面で散乱を少なくするため、平均粒径１００ｎｍの蛍光体微粒子を利用している（例えば、特許文献１参照）。 Solar cells for converting sunlight into electrical energy are clean renewable energy, but in general, only light of some wavelengths of sunlight is used for photoelectric conversion, which is the photoelectric conversion efficiency. It is a factor of decline. Therefore, a wavelength conversion layer that converts light having a wavelength that cannot be used in the solar cell into light having a usable wavelength is provided. In the wavelength conversion layer, phosphor particles having an average particle diameter of 100 nm are used in order to reduce scattering on the surface of the phosphor particles (see, for example, Patent Document 1).
特開２０１１－１４２１７９号公報JP 2011-142179 A 特開２００４－１６１８４１号公報JP 2004-161841 A 特開２００２－１７６２０１号公報JP 2002-176201 A 特開２００９－２０６２１２号公報JP 2009-206212 A 特開２０１４－５２６０６号公報JP 2014-52606 A 特開２０１１－１７１５１２号公報JP 2011-171512 A
　波長変換効率をさらに向上することに加えて、太陽電池が利用可能な波長の光に対する透過率の低下を抑制することが望まれる。 In addition to further improving the wavelength conversion efficiency, it is desired to suppress a decrease in transmittance with respect to light having a wavelength that can be used by the solar cell.
　本発明はこうした状況に鑑みてなされたものであり、その目的は、利用不可能な波長の光を利用可能な波長の光へ変換させながらも、透過率の低下を抑制する技術を提供することにある。 The present invention has been made in view of such circumstances, and an object thereof is to provide a technique for suppressing a decrease in transmittance while converting light having an unusable wavelength into light having a usable wavelength. It is in.
　上記課題を解決するために、本発明のある態様の波長変換フィルタは、透明樹脂と、透明樹脂に混合された蛍光体と、透明樹脂に混合され、蛍光体の発光波長の光よりも、蛍光体の励起波長の光を散乱させる散乱材と、を含む。 In order to solve the above-described problems, a wavelength conversion filter according to an aspect of the present invention includes a transparent resin, a phosphor mixed with the transparent resin, and a fluorescent resin mixed with the transparent resin. A scattering material that scatters light having an excitation wavelength of the body.
　本発明の別の態様は、太陽電池モジュールである。この太陽電池モジュールは、保護部材、封止部材、太陽電池セルが積層された太陽電池モジュールであって、封止部材は、透明樹脂と、透明樹脂に混合された蛍光体と、透明樹脂に混合され、蛍光体の発光波長の光よりも、蛍光体の励起波長の光を散乱させる散乱材と、を含む。 Another aspect of the present invention is a solar cell module. This solar cell module is a solar cell module in which a protective member, a sealing member, and solar cells are stacked, and the sealing member is mixed with a transparent resin, a phosphor mixed with the transparent resin, and the transparent resin. And a scattering material that scatters light having an excitation wavelength of the phosphor rather than light having an emission wavelength of the phosphor.
　本発明によれば、利用不可能な波長の光を利用可能な波長の光へ変換させながらも、透過率の低下を抑制できる。 According to the present invention, it is possible to suppress a decrease in transmittance while converting light having an unusable wavelength into light having a usable wavelength.
本発明の実施例に係る太陽電池モジュールの構成を示す断面図である。It is sectional drawing which shows the structure of the solar cell module which concerns on the Example of this invention. 図１の太陽電池セルの外部量子効率の波長依存性を示す図である。It is a figure which shows the wavelength dependence of the external quantum efficiency of the photovoltaic cell of FIG. 図１の封止部材の構成を示す図である。It is a figure which shows the structure of the sealing member of FIG. 図３の蛍光体の励起スペクトルと発光スペクトルを示す図である。It is a figure which shows the excitation spectrum and emission spectrum of the fluorescent substance of FIG. 図５（ａ）－（ｂ）は、図３の散乱材の粒径が１００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す図である。5A and 5B are diagrams showing the scattering intensity distribution and the scattering intensity distribution in which the component in the straight direction is normalized to 1 when the particle diameter of the scattering material in FIG. 3 is 100 nm. 図６（ａ）－（ｂ）は、図３の散乱材の粒径が３００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す図である。6A and 6B are diagrams showing the scattering intensity distribution and the scattering intensity distribution in which the component in the straight direction is normalized to 1 when the particle size of the scattering material in FIG. 3 is 300 nm. 図７（ａ）－（ｂ）は、図３の散乱材の粒径が５００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す図である。FIGS. 7A and 7B are diagrams showing the scattering intensity distribution when the particle size of the scattering material of FIG. 図８（ａ）－（ｂ）は、図３の散乱材の粒径が１０００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す図である。FIGS. 8A and 8B are diagrams showing the scattering intensity distribution when the particle size of the scattering material of FIG. 図３の散乱材を分散させた封止部材の透過率の波長依存性を示す図である。It is a figure which shows the wavelength dependence of the transmittance | permeability of the sealing member which disperse | distributed the scattering material of FIG. 図３の封止部材の配合条件を示す図である。It is a figure which shows the compounding conditions of the sealing member of FIG. 図１０に示した配合条件のそれぞれに対する透過率の波長依存性を示す図である。It is a figure which shows the wavelength dependence of the transmittance | permeability with respect to each of the mixing conditions shown in FIG.
　本発明の実施例を具体的に説明する前に、基礎となった知見を説明する。本発明の実施例は、太陽電池セルを備えた太陽電池モジュールに関する。太陽電池セルでは、一般的に、紫外線、可視光線の低波長領域の光に対して、可視光線の他の波長領域の光よりも光電変換効率が低い。紫外線、可視光線の低波長領域の光に対する光電変換効率を改善するために、太陽電池セルの封止部材に蛍光体が混合され、蛍光体が、紫外線、可視光線の低波長領域の光に対して波長を変換する。これまでは、一般的に、封止部材の透過率の低下を抑制するために、蛍光体、特に無機蛍光体の粒径は、数十ｎｍにされていた。波長変換効率を向上させるためには、蛍光体の粒径が大きい方が好ましく、例えば、数μｍにされるべきである。しかしながら、蛍光体の粒径が大きくなると、封止部材の透過率が低下することによって、可視光が反射されてしまい、太陽電池セルの光電変換効率が低下してしまう。本実施例では、蛍光体の粒径を大きくすることによって、波長変換効率を向上させながらも、太陽電池セルにおいて光電変換効率の高い波長の光に対する透過率の低下を抑制することを目的とする。 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to specific description of embodiments of the present invention, the knowledge that is the basis will be described. The Example of this invention is related with the solar cell module provided with the photovoltaic cell. Generally, in a solar battery cell, photoelectric conversion efficiency is lower for light in the low wavelength region of ultraviolet light and visible light than in light in other wavelength regions of visible light. In order to improve the photoelectric conversion efficiency for light in the low wavelength region of ultraviolet light and visible light, a phosphor is mixed in the sealing member of the solar battery cell, and the phosphor is in response to light in the low wavelength region of ultraviolet light and visible light. To convert the wavelength. Until now, in general, the particle size of phosphors, particularly inorganic phosphors, has been set to several tens of nm in order to suppress a decrease in transmittance of the sealing member. In order to improve the wavelength conversion efficiency, it is preferable that the phosphor has a larger particle size, and should be, for example, several μm. However, when the particle size of the phosphor is increased, the transmittance of the sealing member is decreased, so that visible light is reflected and the photoelectric conversion efficiency of the solar battery cell is decreased. The purpose of this example is to suppress a decrease in transmittance for light having a high photoelectric conversion efficiency in a solar battery cell while improving the wavelength conversion efficiency by increasing the particle size of the phosphor. .
　図１は、本発明の実施例に係る太陽電池モジュール１００の構成を示す断面図である。太陽電池モジュール１００は、太陽電池セル１０、タブ線１６と総称される第１タブ線１６ａ、第２タブ線１６ｂ、封止部材１８と総称される第１封止部材１８ａ、第２封止部材１８ｂ、保護部材２０と総称される第１保護部材２０ａ、第２保護部材２０ｂを含む。 FIG. 1 is a cross-sectional view showing a configuration of a solar cell module 100 according to an embodiment of the present invention. The solar cell module 100 includes a solar cell 10, a first tab wire 16 a collectively referred to as a tab wire 16, a second tab wire 16 b, a first sealing member 18 a collectively referred to as a sealing member 18, and a second sealing member. 18b, the 1st protection member 20a and the 2nd protection member 20b which are named the protection member 20 generically.
　太陽電池セル１０は、入射する光を吸収して光起電力を発生し、例えば、結晶系シリコン、ガリウム砒素（ＧａＡｓ）またはインジウム燐（ＩｎＰ）等の半導体材料によって形成される。太陽電池セル１０の構造は、特に限定されないが、ここでは、一例として、結晶シリコンとアモルファスシリコンとが積層されているとする。太陽電池セル１０は、太陽電池セル１０の表面のひとつである受光面１２と、受光面１２に背向する裏面１４とを有する。ここで、受光面１２とは、太陽電池セル１０において主に太陽光が入射される主面を意味し、具体的には、太陽電池セル１０に入射される光の大部分が入射される面である。また、受光面１２と裏面１４とには、図示しない電極が設けられる。 The solar battery cell 10 absorbs incident light and generates a photovoltaic power, and is formed of a semiconductor material such as crystalline silicon, gallium arsenide (GaAs), or indium phosphorus (InP). The structure of the solar battery cell 10 is not particularly limited, but here, as an example, it is assumed that crystalline silicon and amorphous silicon are stacked. The solar battery cell 10 has a light receiving surface 12 that is one of the surfaces of the solar battery cell 10 and a back surface 14 facing away from the light receiving surface 12. Here, the light receiving surface 12 means a main surface on which solar light is mainly incident in the solar battery cell 10, and specifically, a surface on which most of the light incident on the solar battery cell 10 is incident. It is. Further, electrodes (not shown) are provided on the light receiving surface 12 and the back surface 14.
　このような太陽電池セル１０の特性を説明する。図２は、太陽電池セル１０の外部量子効率の波長依存性を示す。横軸が波長を示し、縦軸が太陽電池セル１０の外部量子効率を示す。外部量子効率とは、太陽電池セル１０に入射される光子数に対して、太陽電池セル１０から出力される電子数を割合で示したものであり、外部量子効率が高いほど光電変換効率が高いといえる。５００ｎｍ以上の波長において、外部量子効率はほぼ一定の高い値を示す。このような波長は、可視光の緑色光よりも高い波長といえる。一方、５００ｎｍよりも短い波長において、波長が短くなるほど、外部量子効率は低下する。特に、５００ｎｍから４５０ｎｍの波長よりも、４５０ｎｍ以下の波長において、波長に対する外部量子効率の傾きが急になる。前者の波長は、可視光の青色光の波長に相当し、後者の波長は、可視光の紫色光、紫外線光に相当する。図１に戻る。 The characteristics of such a solar battery cell 10 will be described. FIG. 2 shows the wavelength dependence of the external quantum efficiency of the solar battery cell 10. The horizontal axis indicates the wavelength, and the vertical axis indicates the external quantum efficiency of the solar battery cell 10. The external quantum efficiency is the ratio of the number of electrons output from the solar cell 10 to the number of photons incident on the solar cell 10, and the higher the external quantum efficiency, the higher the photoelectric conversion efficiency. It can be said. At a wavelength of 500 nm or more, the external quantum efficiency shows a substantially constant high value. It can be said that such a wavelength is higher than that of visible green light. On the other hand, at a wavelength shorter than 500 nm, the external quantum efficiency decreases as the wavelength becomes shorter. In particular, the slope of the external quantum efficiency with respect to the wavelength becomes steeper at the wavelength of 450 nm or less than the wavelength of 500 nm to 450 nm. The former wavelength corresponds to the wavelength of visible blue light, and the latter wavelength corresponds to violet light and ultraviolet light of visible light. Returning to FIG.
　タブ線１６は、図示しない電極に電気的に導通するように、受光面１２および裏面１４上に接着される。なお、タブ線１６と電極とは、樹脂層を介して接続されてもよい。タブ線１６は、複数の太陽電池セル１０が配列される図１の横方向に延び、隣接する一方の太陽電池セル１０の受光面１２側の電極と、他方の太陽電池セル１０（図示せず）の裏面１４側の電極とを接続する。 The tab wire 16 is adhered on the light receiving surface 12 and the back surface 14 so as to be electrically connected to an electrode (not shown). The tab wire 16 and the electrode may be connected via a resin layer. The tab line 16 extends in the horizontal direction of FIG. 1 where a plurality of solar cells 10 are arranged, and the electrode on the light receiving surface 12 side of one adjacent solar cell 10 and the other solar cell 10 (not shown). ) On the back surface 14 side.
　第１保護部材２０ａは、太陽電池セル１０の受光面１２側に設けられ、太陽電池セル１０を外部環境から保護するとともに、太陽電池セル１０に吸収させるべき光を透過する。第１保護部材２０ａは、例えば、ガラス基板である。なお、第１保護部材２０ａは、ガラス基板の他に、ポリカーボネート、アクリル、ポリエステル、フッ化ポリエチレンであってもよい。第２保護部材２０ｂは、太陽電池セル１０の裏面１４側に設けられるバックシートである。第２保護部材２０ｂは、第１保護部材２０ａと同じガラスや、プラスチック等の透明基板としてもよい。また、第１保護部材２０ａ側から入射した光が太陽電池セル１０により多く吸収されるよう、第２保護部材２０ｂと第２封止部材１８ｂの間に金属箔などを設けることで、第１保護部材２０ａから第２保護部材２０ｂに達した光を太陽電池セル１０の方向に反射させてもよい。 The first protective member 20a is provided on the light receiving surface 12 side of the solar battery cell 10, and protects the solar battery cell 10 from the external environment and transmits light to be absorbed by the solar battery cell 10. The first protection member 20a is, for example, a glass substrate. The first protective member 20a may be polycarbonate, acrylic, polyester, or fluorinated polyethylene in addition to the glass substrate. The second protective member 20 b is a back sheet provided on the back surface 14 side of the solar battery cell 10. The second protective member 20b may be the same glass as the first protective member 20a or a transparent substrate such as plastic. Further, by providing a metal foil or the like between the second protective member 20b and the second sealing member 18b so that a large amount of light incident from the first protective member 20a side is absorbed by the solar battery cell 10, the first protection is achieved. The light reaching the second protective member 20b from the member 20a may be reflected in the direction of the solar battery cell 10.
　封止部材１８は、第１保護部材２０ａと受光面１２との間、第２保護部材２０ｂと裏面１４との間にそれぞれ設けられ、太陽電池セル１０への水分の浸入等を防ぐとともに、太陽電池モジュール１００全体の強度を向上させる保護材である。このように、太陽電池モジュール１００では、第１保護部材２０ａ、第１封止部材１８ａ、太陽電池セル１０、第２封止部材１８ｂ、第２バックシート２２ｂが積層される。さらに、封止部材１８は、波長変換フィルタとしての機能も有する。以下では、封止部材１８の構成をさらに詳細に説明する。 The sealing member 18 is provided between the first protection member 20a and the light receiving surface 12, and between the second protection member 20b and the back surface 14, respectively, and prevents moisture from entering the solar cells 10 and the like. It is a protective material that improves the overall strength of the battery module 100. Thus, in the solar cell module 100, the 1st protection member 20a, the 1st sealing member 18a, the photovoltaic cell 10, the 2nd sealing member 18b, and the 2nd back sheet 22b are laminated | stacked. Furthermore, the sealing member 18 also has a function as a wavelength conversion filter. Hereinafter, the configuration of the sealing member 18 will be described in more detail.
　図３は、封止部材１８の構成を示す。封止部材１８は、蛍光体３０、散乱材３２、透明樹脂３４を含む。透明樹脂３４は、太陽光を十分に透過可能な透明性を有する。例えば、透明樹脂３４は、エチレン酢酸ビニル共重合体（ＥＶＡ）や、ポリビニルブチラール（ＰＶＢ）、ポリイミド、ポリエチレン、ポリプロピレン、ポリエチレンテレフタレート（ＰＥＴ）等の樹脂材料である。ここでは、ＥＶＡであるとする。 FIG. 3 shows the configuration of the sealing member 18. The sealing member 18 includes a phosphor 30, a scattering material 32, and a transparent resin 34. The transparent resin 34 has transparency that can sufficiently transmit sunlight. For example, the transparent resin 34 is a resin material such as ethylene vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), polyimide, polyethylene, polypropylene, polyethylene terephthalate (PET). Here, it is assumed that it is EVA.
　蛍光体３０は、透明樹脂３４に混合されており、太陽光に含まれる一部の波長の光に対して波長を変換する。前述のごとく、太陽電池セル１０の光電変換効率を向上させるために、蛍光体３０は、太陽電池セル１０での光電変換効率の低い短波長域の光を吸収し、光電変換効率の高い長波長域の光を発光する。具体的に説明すると、蛍光体３０は、５００ｎｍ以下の紫外光～青色光に対して、５００ｎｍ～１１００ｎｍの緑色光～近赤外光へ波長変換する。特に、蛍光体３０では、太陽光スペクトル強度が相対的に大きい３００ｎｍ以上で効率的に励起される。また、蛍光体３０には、耐久性および耐湿性の点から、無機蛍光体が使用される。 The phosphor 30 is mixed in the transparent resin 34 and converts the wavelength of light having a part of the wavelength contained in sunlight. As described above, in order to improve the photoelectric conversion efficiency of the solar battery cell 10, the phosphor 30 absorbs light in a short wavelength region where the photoelectric conversion efficiency in the solar battery cell 10 is low, and the long wavelength with high photoelectric conversion efficiency. The light of the region is emitted. More specifically, the phosphor 30 converts the wavelength of ultraviolet light to blue light of 500 nm or less from green light to near infrared light of 500 nm to 1100 nm. In particular, the phosphor 30 is efficiently excited at 300 nm or more where the sunlight spectrum intensity is relatively large. In addition, an inorganic phosphor is used for the phosphor 30 from the viewpoint of durability and moisture resistance.
　前述のごとく、蛍光体３０の粒径が数μｍであると、波長変換効率は向上するものの、透過率が低下する。透過率が低下すると、蛍光体３０による反射によって、太陽電池セル１０に向かわずに太陽光が入射する側に反射する光の成分が生じる。反射する光の成分が発生すると、太陽電池セル１０の光電変換効率が低下する。ここでは、波長変換効率を向上させるために、蛍光体３０の粒径を数μｍとするとともに、５００ｎｍ以上の透過率の低下を抑制するために、散乱材３２も透明樹脂３４に混合させる。散乱材３２については、後述する。なお、複数の蛍光体３０の粒径は、均一でなくてもよく、その場合は平均粒径を数μｍとすればよい。平均粒径の測定には、公知の技術が使用されればよいので、ここでは説明を省略する。 As described above, when the particle size of the phosphor 30 is several μm, the wavelength conversion efficiency is improved, but the transmittance is lowered. When the transmittance is reduced, reflection by the phosphor 30 generates a component of light that is reflected toward the side on which sunlight is incident without going to the solar battery cell 10. When the component of the reflected light is generated, the photoelectric conversion efficiency of the solar battery cell 10 is lowered. Here, in order to improve the wavelength conversion efficiency, the particle size of the phosphor 30 is set to several μm, and the scattering material 32 is also mixed with the transparent resin 34 in order to suppress a decrease in transmittance of 500 nm or more. The scattering material 32 will be described later. The particle diameters of the plurality of phosphors 30 may not be uniform, and in that case, the average particle diameter may be several μm. Since a known technique may be used for the measurement of the average particle diameter, description thereof is omitted here.
　蛍光体３０の一例として、（Ｂａ，Ｓｒ）２ＳｉＯ４：Ｅｕが使用される。図４は、蛍光体３０である（Ｂａ，Ｓｒ）２ＳｉＯ４：Ｅｕの励起スペクトルと発光スペクトルを示す。横軸が波長を示し、縦軸が強度（任意単位）を示す。図示のごとく、励起スペクトル４０、発光スペクトル４２が示される。励起スペクトル４０は、蛍光体３０によって吸収される光の強度の波長変化を示す。励起ピークＰ１は、励起スペクトル４０における強度の最大値であり、その波長は約３００ｎｍである。また、励起波長域４４は、励起ピークＰ１の強度の半分の値以上となる強度を有する波長幅であり、これは、励起ピークＰ１の強度に対する半値幅に相当する。なお、励起波長域４４は、励起ピークＰ１の強度の半分の値とは異なった値によって特定されてもよい。図４における励起波長域４４は、約２６０ｎｍから約４９０ｎｍにわたって規定される。さらに、蛍光体３０によって励起される光の波長を「励起波長」と総称する。そのため、励起波長によって、励起スペクトル４０全体が特定されてもよく、励起波長域４４のような励起スペクトル４０の一部が特定されてもよく、励起ピークＰ１のような励起スペクトル４０中の１点が特定されてもよい。 As an example of the phosphor 30, (Ba, Sr) 2 SiO 4 : Eu is used. FIG. 4 shows an excitation spectrum and an emission spectrum of (Ba, Sr) 2 SiO 4 : Eu that is the phosphor 30. The horizontal axis indicates the wavelength, and the vertical axis indicates the intensity (arbitrary unit). As shown, an excitation spectrum 40 and an emission spectrum 42 are shown. The excitation spectrum 40 shows a change in wavelength of the intensity of light absorbed by the phosphor 30. The excitation peak P1 is the maximum intensity in the excitation spectrum 40, and the wavelength thereof is about 300 nm. The excitation wavelength region 44 has a wavelength width that has an intensity that is equal to or greater than half the intensity of the excitation peak P1, and this corresponds to a half-value width with respect to the intensity of the excitation peak P1. The excitation wavelength region 44 may be specified by a value different from the half value of the intensity of the excitation peak P1. The excitation wavelength region 44 in FIG. 4 is defined from about 260 nm to about 490 nm. Furthermore, the wavelength of light excited by the phosphor 30 is collectively referred to as “excitation wavelength”. Therefore, the entire excitation spectrum 40 may be specified by the excitation wavelength, a part of the excitation spectrum 40 such as the excitation wavelength region 44 may be specified, and one point in the excitation spectrum 40 such as the excitation peak P1. May be specified.
　発光スペクトル４２は、蛍光体３０から発光される光の強度の波長変化を示す。発光ピークＱ１は、発光スペクトル４２における強度の最大値であり、その波長は５４０ｎｍである。また、発光波長域４６は、発光ピークＱ１に対して、励起波長域４４と同様に規定される。図４における発光波長域４６は、約５１０ｎｍから約５７０ｎｍにわたって規定される。さらに、蛍光体３０から発光される光の波長を「発光波長」と総称する。そのため、発光波長によって、発光スペクトル４２全体が特定されてもよく、発光波長域４６のような発光スペクトル４２の一部が特定されてもよく、発光ピークＱ１のような発光スペクトル４２中の１点が特定されてもよい。図３に戻る。 The emission spectrum 42 shows the wavelength change of the intensity of the light emitted from the phosphor 30. The emission peak Q1 is the maximum intensity in the emission spectrum 42, and its wavelength is 540 nm. The emission wavelength region 46 is defined in the same manner as the excitation wavelength region 44 with respect to the emission peak Q1. The emission wavelength region 46 in FIG. 4 is defined from about 510 nm to about 570 nm. Further, the wavelength of light emitted from the phosphor 30 is collectively referred to as “emission wavelength”. Therefore, the entire emission spectrum 42 may be specified by the emission wavelength, a part of the emission spectrum 42 such as the emission wavelength region 46 may be specified, and one point in the emission spectrum 42 such as the emission peak Q1. May be specified. Returning to FIG.
　散乱材３２は、粒形状を有する。また、散乱材３２は、波長の選択性を有しながら、光を散乱させる。散乱材３２は、例えば、二酸化ケイ素（ＳｉＯ２）であり、これは、シリカ、無水ケイ酸とも呼ばれる。また、散乱材３２は、例えば、酸化ジルコニウム（ＩＶ）（ＺｒＯ２）であり、これは、ジルコニアとも呼ばれる。ここでは、散乱材３２がＳｉＯ２であるとする。 The scattering material 32 has a grain shape. The scattering material 32 scatters light while having wavelength selectivity. The scattering material 32 is, for example, silicon dioxide (SiO 2 ), which is also called silica or silicic anhydride. The scattering material 32 is, for example, zirconium oxide (IV) (ZrO 2 ), which is also called zirconia. Here, it is assumed that the scattering material 32 is SiO 2 .
　散乱材３２に要求される波長の選択性は、次の２つの特性によって示される。ひとつ目の特性は、蛍光体３０の励起波長、例えば、励起ピークＰ１あるいは励起波長域４４において、透過率が低くなることである。これは、蛍光体３０が（Ｂａ，Ｓｒ）２ＳｉＯ４：Ｅｕである場合に、５００ｎｍ以下の波長の光を散乱させることに相当する。透過率が低くなることによって、その波長の光は、散乱材３２で散乱され、蛍光体３０に吸収されやすくなる。また、２つ目の特性は、蛍光体３０の発光波長、例えば、発光ピークＱ１あるいは発光波長域４６において、透過率が高くなることである。この波長の光は、太陽電池セル１０における光電変換効率が高いので、そのまま太陽電池セル１０に吸収されることが望ましい。なお、蛍光体３０の発光波長よりも長い波長の光に対しても、蛍光体３０の透過率は高い方が望ましい。これらをまとめると、散乱材３２は、蛍光体３０の発光波長の光よりも、蛍光体３０の励起波長の光を散乱させるといえる。 The wavelength selectivity required for the scattering material 32 is indicated by the following two characteristics. The first characteristic is that the transmittance is low at the excitation wavelength of the phosphor 30, for example, at the excitation peak P <b> 1 or the excitation wavelength region 44. This corresponds to scattering light having a wavelength of 500 nm or less when the phosphor 30 is (Ba, Sr) 2 SiO 4 : Eu. By reducing the transmittance, light of that wavelength is scattered by the scattering material 32 and is easily absorbed by the phosphor 30. The second characteristic is that the transmittance is high at the emission wavelength of the phosphor 30, for example, at the emission peak Q 1 or the emission wavelength region 46. Since the light of this wavelength has high photoelectric conversion efficiency in the solar cell 10, it is desirable that the light is absorbed as it is by the solar cell 10. Note that it is desirable that the transmittance of the phosphor 30 is high even for light having a wavelength longer than the emission wavelength of the phosphor 30. In summary, it can be said that the scattering material 32 scatters light having an excitation wavelength of the phosphor 30 rather than light having an emission wavelength of the phosphor 30.
　図５（ａ）－（ｂ）は、散乱材３２の粒径が１００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す。図５（ａ）が散乱強度分布を示し、図５（ｂ）が規格化した散乱強度分布を示す。これらは、ＳｉＯ２がＥＶＡに含まれた状態において測定されている。また、照射する光の波長は、３５０ｎｍ、５５０ｎｍ、１０００ｎｍである。３５０ｎｍは励起波長域４４に含まれ、５５０ｎｍは発光波長域４６に含まれ、１０００ｎｍは発光波長よりも長い波長である。図５（ａ）のごとく、散乱強度の方向依存性は低い。また、波長３５０ｎｍ結果９０の散乱強度が最大であり、波長５５０ｎｍ結果９２の散乱強度が次に大きく、波長１０００ｎｍ結果９４の散乱強度が最小である。つまり、波長が短くなるほど、散乱強度が大きくなる。図５（ｂ）のごとく、波長３５０ｎｍ結果９０の指向性は、波長５５０ｎｍ結果９２の指向性よりも大きく、波長５５０ｎｍ結果９２の指向性は、波長１０００ｎｍ結果９４の指向性よりも大きい。つまり、波長が短くなるほど、指向性が大きくなる。なお、指向性が大きくなると、前方散乱だけの傾向が強くなり、指向性が小さくなると、後方散乱も増えてくる。 FIGS. 5A and 5B show the scattering intensity distribution when the particle size of the scattering material 32 is 100 nm and the scattering intensity distribution in which the straight direction component is normalized to 1. FIG. FIG. 5A shows the scattered intensity distribution, and FIG. 5B shows the normalized scattered intensity distribution. These are measured in a state where SiO 2 is contained in EVA. Moreover, the wavelength of the light to irradiate is 350 nm, 550 nm, and 1000 nm. 350 nm is included in the excitation wavelength region 44, 550 nm is included in the emission wavelength region 46, and 1000 nm is a wavelength longer than the emission wavelength. As shown in FIG. 5A, the direction dependency of the scattering intensity is low. Further, the scattering intensity at the wavelength 350 nm result 90 is the largest, the scattering intensity at the wavelength 550 nm result 92 is the next largest, and the scattering intensity at the wavelength 1000 nm result 94 is the smallest. That is, the shorter the wavelength, the greater the scattering intensity. As shown in FIG. 5B, the directivity of the wavelength 350 nm result 90 is larger than the directivity of the wavelength 550 nm result 92, and the directivity of the wavelength 550 nm result 92 is larger than the directivity of the wavelength 1000 nm result 94. That is, the directivity increases as the wavelength becomes shorter. As the directivity increases, the tendency of only forward scattering increases, and when the directivity decreases, the backscatter increases.
　図６（ａ）－（ｂ）は、散乱材３２の粒径が３００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す。図６（ａ）－（ｂ）は、図５（ａ）－（ｂ）と同様に示される。図６（ａ）と図５（ａ）とを比較すると、散乱材３２の粒径が１００ｎｍである場合よりも、散乱材３２の粒径が３００ｎｍである場合の方が、散乱強度が大きくなっている。また、図６（ｂ）と図５（ｂ）とを比較すると、散乱材３２の粒径が１００ｎｍである場合よりも、散乱材３２の粒径が３００ｎｍである場合の方が、波長による指向性の違いが小さくなっている。 6 (a)-(b) show the scattering intensity distribution when the particle size of the scattering material 32 is 300 nm and the scattering intensity distribution in which the component in the straight direction is normalized to 1. FIG. 6 (a)-(b) are shown similarly to FIGS. 5 (a)-(b). Comparing FIG. 6A and FIG. 5A, the scattering intensity is larger when the particle size of the scattering material 32 is 300 nm than when the particle size of the scattering material 32 is 100 nm. ing. Further, when FIG. 6B and FIG. 5B are compared, the wavelength-oriented direction is more when the particle size of the scattering material 32 is 300 nm than when the particle size of the scattering material 32 is 100 nm. The difference in sex is getting smaller.
　図７（ａ）－（ｂ）は、散乱材３２の粒径が５００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す。図７（ａ）－（ｂ）も、図５（ａ）－（ｂ）と同様に示される。図７（ａ）は、図６（ａ）よりも散乱強度が大きくなっており、図７（ｂ）は、図６（ｂ）よりも波長による指向性の違いが小さくなっている。 7 (a)-(b) show the scattering intensity distribution when the particle size of the scattering material 32 is 500 nm and the scattering intensity distribution in which the straight direction component is normalized to 1. FIG. 7 (a)-(b) are also shown in the same manner as FIGS. 5 (a)-(b). In FIG. 7A, the scattering intensity is larger than in FIG. 6A, and in FIG. 7B, the difference in directivity depending on the wavelength is smaller than in FIG. 6B.
　図８（ａ）－（ｂ）は、散乱材３２の粒径が１０００ｎｍである場合の散乱強度分布および直進方向成分を１と規格化した散乱強度分布を示す。図８（ａ）－（ｂ）も、図５（ａ）－（ｂ）と同様に示される。図８（ａ）より、散乱材３２の粒径が１０００ｎｍである場合に、今回シミュレーションした中で、散乱強度が最大になっている。図８（ｂ）より、散乱材３２の粒径が１０００ｎｍである場合に、今回測定した中で、波長による指向性の違いが最小になっている。図５（ａ）－（ｂ）、図６（ａ）－（ｂ）、図７（ａ）－（ｂ）、図８（ａ）－（ｂ）より、粒径が小さくなると、後方散乱しやすい傾向となり、波長が大きくなっても、後方散乱しやすい傾向になる。また、粒径が小さくなると、波長の選択性が大きくなるが、散乱強度が小さくなる。さらに、粒径が大きくなると、波長の選択性が小さくなるが、散乱強度が大きくなる。そのため、波長の選択性が大きく、かつ散乱強度も大きくなるように、粒径が決定されるべきである。シミュレーションの結果からはおよそ５００ｎｍの粒子から波長選択性が現れており、選択性のある散乱材としては利用可能であると想定される。 FIGS. 8A to 8B show the scattering intensity distribution when the particle diameter of the scattering material 32 is 1000 nm and the scattering intensity distribution in which the straight direction component is normalized to 1. FIG. 8 (a)-(b) are also shown in the same manner as FIGS. 5 (a)-(b). As shown in FIG. 8A, when the particle size of the scattering material 32 is 1000 nm, the scattering intensity is maximized in this simulation. From FIG. 8B, when the particle size of the scattering material 32 is 1000 nm, the difference in directivity due to the wavelength is minimized among the measurements made this time. From FIG. 5 (a)-(b), FIG. 6 (a)-(b), FIG. 7 (a)-(b), and FIG. 8 (a)-(b), as the particle size becomes smaller, backscattering occurs. It tends to be easily scattered, and even if the wavelength is increased, it tends to be easily backscattered. Also, as the particle size decreases, the wavelength selectivity increases, but the scattering intensity decreases. Furthermore, as the particle size increases, the wavelength selectivity decreases, but the scattering intensity increases. Therefore, the particle size should be determined so that the wavelength selectivity is large and the scattering intensity is also large. As a result of simulation, wavelength selectivity appears from particles of about 500 nm, and it is assumed that it can be used as a selective scattering material.
　図９は、散乱材３２を分散させた封止部材１８の透過率の波長依存性を示す。横軸が波長を示し、縦軸が透過率を示す。１０００ｎｍ散乱材５４では、測定したすべての波長、特に励起波長域４４、発光波長域４６において、透過率の変化が小さい。一方、１００ｎｍ散乱材５０、３００ｎｍ散乱材５２では、発光波長域４６における透過率よりも、励起波長域４４における透過率の方が低くなっている。このように、散乱材３２の粒径が小さくなるほど、波長の短い光だけが散乱されるようになり、波長選択性が生じる。以上の結果、１００ｎｍ散乱材５０、３００ｎｍ散乱材５２は、前述の２つの特性を有し、１０００ｎｍ散乱材５４は、前述の２つの特性に対する特性を有さない。ここで、図９に図示していないが、５００ｎｍ散乱材は、前述の２つの特性を有する。よって、これらを考慮して、散乱材３２の粒径の平均は、５００ｎｍ以下とされるべきである。 FIG. 9 shows the wavelength dependence of the transmittance of the sealing member 18 in which the scattering material 32 is dispersed. The horizontal axis indicates the wavelength, and the vertical axis indicates the transmittance. In the 1000 nm scattering material 54, the change in transmittance is small in all measured wavelengths, particularly in the excitation wavelength region 44 and the emission wavelength region 46. On the other hand, in the 100 nm scattering material 50 and the 300 nm scattering material 52, the transmittance in the excitation wavelength region 44 is lower than the transmittance in the emission wavelength region 46. Thus, as the particle size of the scattering material 32 becomes smaller, only light having a shorter wavelength is scattered, resulting in wavelength selectivity. As a result, the 100 nm scattering material 50 and the 300 nm scattering material 52 have the above-described two characteristics, and the 1000 nm scattering material 54 does not have characteristics with respect to the above-described two characteristics. Here, although not shown in FIG. 9, the 500 nm scattering material has the above-described two characteristics. Therefore, in consideration of these, the average particle diameter of the scattering material 32 should be 500 nm or less.
　図１０は、封止部材１８の配合条件を示す。ここでは、４種類の配合条件を示しており、そのうちの２つが実施例に対応した第１パターンと第２パターンであり、残りの２つが実施例と比較するための第１比較例と第２比較例である。４種類の配合条件において、蛍光体３０と透明樹脂３４とに対する条件は共通であり、散乱材３２に対する条件はすべて異なる。図示のごとく、蛍光体３０の組成は、（Ｂａ，Ｓｒ）２ＳｉＯ４：Ｅｕであり、その添加量は１．０体積％であり、その粒径は１６０００ｎｍである。また、透明樹脂３４の組成はＥＶＡであり、その屈折率は１．４８である。 FIG. 10 shows the blending conditions of the sealing member 18. Here, four kinds of blending conditions are shown, two of which are the first pattern and the second pattern corresponding to the example, and the remaining two are the first comparative example and the second pattern for comparison with the example. It is a comparative example. In the four kinds of blending conditions, the conditions for the phosphor 30 and the transparent resin 34 are common, and the conditions for the scattering material 32 are all different. As shown in the drawing, the composition of the phosphor 30 is (Ba, Sr) 2 SiO 4 : Eu, the addition amount is 1.0% by volume, and the particle size is 16000 nm. The composition of the transparent resin 34 is EVA, and the refractive index thereof is 1.48.
　第１パターン、第２パターン、第２比較例における散乱材３２の組成はＳｉＯ２であり、その屈折率は１．４４である。第１パターンにおけるＳｉＯ２の添加量は５．０体積％であり、粒径は１００ｎｍであり、第２パターンにおけるＳｉＯ２の添加量は８．０体積％であり、粒径は３００ｎｍであり、第２比較例におけるＳｉＯ２の添加量は１０．０体積％であり、粒径は１０００ｎｍである。これらは、既に比較した３種類の粒径に相当する。一方、第１比較例には、散乱材３２が混合されていない。 The composition of the scattering material 32 in the first pattern, the second pattern, and the second comparative example is SiO 2 and its refractive index is 1.44. The amount of SiO 2 added in the first pattern is 5.0% by volume and the particle size is 100 nm, the amount of SiO 2 added in the second pattern is 8.0% by volume, and the particle size is 300 nm. The amount of SiO 2 added in the second comparative example is 10.0% by volume, and the particle size is 1000 nm. These correspond to the three particle sizes already compared. On the other hand, the scattering material 32 is not mixed in the first comparative example.
　図１１は、前述の配合条件のそれぞれに対する透過率の波長依存性を示す。横軸が波長を示し、縦軸が透過率を示す。第１比較例６４には、散乱材３２が混合されていないので、測定した全波長にわたって透過率が高くなっている。そのため、励起波長域４４における蛍光体３０への光の吸収量が少なくなり、蛍光体３０によって波長変換される光の量も減少する。その結果、太陽電池セル１０による光電変換効率の向上も少ない。第２比較例６６には、波長選択性のない散乱材３２が混合されているので、測定した全波長にわたって透過率が低くなっている。特に、発光波長域４６およびそれ以上の波長における透過率が低下しているので、太陽電池セル１０による光電効果も低下する。 FIG. 11 shows the wavelength dependence of the transmittance for each of the aforementioned blending conditions. The horizontal axis indicates the wavelength, and the vertical axis indicates the transmittance. Since the scattering material 32 is not mixed in the first comparative example 64, the transmittance is high over all the measured wavelengths. Therefore, the amount of light absorbed by the phosphor 30 in the excitation wavelength region 44 is reduced, and the amount of light wavelength-converted by the phosphor 30 is also reduced. As a result, there is little improvement in photoelectric conversion efficiency by the solar battery cell 10. In the second comparative example 66, since the scattering material 32 having no wavelength selectivity is mixed, the transmittance is low over all measured wavelengths. In particular, since the transmittance at the emission wavelength region 46 and above is reduced, the photoelectric effect by the solar battery cell 10 is also reduced.
　第１パターン６０および第２パターン６２は、励起波長域４４において、第２比較例６６と同様に透過率が低下している。そのため、励起波長域４４における蛍光体３０への光の吸収量が多くなり、蛍光体３０によって波長変換される光の量も増加する。また、第１パターン６０および第２パターン６２では、第１比較例６４と比較して、発光波長域４６およびそれ以上の波長における透過率の低下が少ない。その結果、太陽電池セル１０による光電変換効率が向上する。 The transmittance of the first pattern 60 and the second pattern 62 is reduced in the excitation wavelength region 44 as in the second comparative example 66. Therefore, the amount of light absorbed by the phosphor 30 in the excitation wavelength region 44 increases, and the amount of light that is wavelength-converted by the phosphor 30 also increases. Further, in the first pattern 60 and the second pattern 62, the transmittance is less reduced in the light emission wavelength region 46 and in the wavelength longer than that in the first comparative example 64. As a result, the photoelectric conversion efficiency by the solar battery cell 10 is improved.
　前述のごとく、散乱材３２には、ＳｉＯ２でなく、ＺｒＯ２が使用されてもよい。図１０の配合条件における蛍光体３０、透明樹脂３４に対して、散乱材３２としてＺｒＯ２を混合することが可能である。ＺｒＯ２の屈折率は２．２であり、例えば、添加量が０．００５体積％であり、粒径が１５０ｎｍとされる。ＳｉＯ２とＥＶＡとの屈折率の差は「０．０４」であり、ＺｒＯ２とＥＶＡと屈折率の差は、「１．０４」である。後者の方が前者よりも、屈折率の差が大きくなる。屈折率の差が大きくなるほど、光が散乱しやすくなる。そのため、ＳｉＯ２にとっての適量だけ、ＺｒＯ２を混合すると、光が散乱しすぎてしまい、波長選択性がなくなってしまう。このように、散乱材３２の添加量は、散乱材３２の屈折率と透明樹脂３４の屈折率との差に応じて決定されており、具体的には、差が小さいほど増やされる。 As described above, the scattering material 32 may be made of ZrO 2 instead of SiO 2 . It is possible to mix ZrO 2 as the scattering material 32 with respect to the phosphor 30 and the transparent resin 34 under the blending conditions of FIG. The refractive index of ZrO 2 is 2.2, for example, the addition amount is 0.005% by volume, and the particle size is 150 nm. The difference in refractive index between SiO 2 and EVA is “0.04”, and the difference in refractive index between ZrO 2 and EVA is “1.04”. The latter has a larger difference in refractive index than the former. The greater the difference in refractive index, the easier it is for light to scatter. Therefore, when ZrO 2 is mixed in an appropriate amount for SiO 2 , light is scattered too much and wavelength selectivity is lost. Thus, the addition amount of the scattering material 32 is determined according to the difference between the refractive index of the scattering material 32 and the refractive index of the transparent resin 34. Specifically, the addition amount is increased as the difference is smaller.
　本発明の実施例によれば、波長変換フィルタにおいて、波長選択性を有した散乱材３２に、粒径の大きな蛍光体３０を混合するので、波長の変換効率を向上させながらも、太陽電池セル１０において効率的に光電変換される波長の光に対する透過率の低下を抑制できる。また、波長の変換効率を向上させながらも、太陽電池セル１０において効率的に光電変換される波長の光に対する透過率の低下が抑制されるので、太陽電池セル１０の光電変換効率を向上できる。また、５００ｎｍ以下の波長の光を散乱させる散乱材３２を使用するので、励起波長の光を効率的に蛍光体３０に吸収させることができる。また、粒径の平均が５００ｎｍ以下の散乱材３２を使用するので、５００ｎｍ以下の波長の光を散乱させることができる。また、散乱材３２の屈折率と透明樹脂３４の屈折率との差が小さいほど、散乱材３２の添加量が増やされるので、波長選択性を有するために適した量の散乱材３２を混合できる。 According to the embodiment of the present invention, since the phosphor 30 having a large particle size is mixed with the scattering material 32 having wavelength selectivity in the wavelength conversion filter, the solar battery cell is improved while improving the wavelength conversion efficiency. 10 can suppress a decrease in transmittance with respect to light having a wavelength that is efficiently photoelectrically converted. Moreover, since the fall of the transmittance | permeability with respect to the light of the wavelength efficiently photoelectrically converted in the photovoltaic cell 10 is suppressed, improving the conversion efficiency of a wavelength, the photoelectric conversion efficiency of the photovoltaic cell 10 can be improved. In addition, since the scattering material 32 that scatters light having a wavelength of 500 nm or less is used, the phosphor 30 can efficiently absorb light having an excitation wavelength. In addition, since the scattering material 32 having an average particle size of 500 nm or less is used, light having a wavelength of 500 nm or less can be scattered. Moreover, since the addition amount of the scattering material 32 is increased as the difference between the refractive index of the scattering material 32 and the refractive index of the transparent resin 34 is smaller, an amount of the scattering material 32 suitable for having wavelength selectivity can be mixed. .
　本実施例の概要は、次の通りである。本発明のある態様の波長変換フィルタ１８は、透明樹脂３４と、透明樹脂３４に混合された蛍光体３０と、透明樹脂３４に混合され、蛍光体３０の発光波長の光よりも、蛍光体３０の励起波長の光を散乱させる散乱材３２と、を含む。 The outline of this example is as follows. The wavelength conversion filter 18 according to an aspect of the present invention includes a transparent resin 34, a phosphor 30 mixed with the transparent resin 34, and a phosphor 30 mixed with the transparent resin 34, rather than light having an emission wavelength of the phosphor 30. And a scattering material 32 that scatters light of the excitation wavelength.
　散乱材３２は、５００ｎｍ以下の波長の光を散乱させてもよい。 The scattering material 32 may scatter light having a wavelength of 500 nm or less.
　散乱材３２は、粒形状を有しており、粒径の平均が５００ｎｍ以下であってもよい。 The scattering material 32 has a grain shape, and the average particle diameter may be 500 nm or less.
　散乱材３２の添加量は、散乱材３２の屈折率と透明樹脂３４の屈折率との差が小さいほど増やされてもよい。 The addition amount of the scattering material 32 may be increased as the difference between the refractive index of the scattering material 32 and the refractive index of the transparent resin 34 is smaller.
　本発明の別の態様は、太陽電池モジュール１００である。この太陽電池モジュール１００は、保護部材２０、封止部材１８、太陽電池セル１０が積層された太陽電池モジュール１００であって、封止部材１８は、透明樹脂３４と、透明樹脂３４に混合された蛍光体３０と、透明樹脂３４に混合され、蛍光体３０の発光波長の光よりも、蛍光体３０の励起波長の光を散乱させる散乱材３２と、を含む。 Another aspect of the present invention is a solar cell module 100. This solar cell module 100 is a solar cell module 100 in which a protective member 20, a sealing member 18, and solar cells 10 are stacked. The sealing member 18 is mixed with a transparent resin 34 and a transparent resin 34. It includes a phosphor 30 and a scattering material 32 that is mixed in the transparent resin 34 and scatters light having an excitation wavelength of the phosphor 30 rather than light having an emission wavelength of the phosphor 30.
　以上、本発明を実施例をもとに説明した。この実施例は例示であり、それらの各構成要素の組合せにいろいろな変形例が可能なこと、またそうした変形例も本発明の範囲にあることは当業者に理解されるところである。 The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements, and such modifications are also within the scope of the present invention.
　本発明の実施例において、蛍光体３０、散乱材３２が透明樹脂３４に混合された波長変換フィルタは、封止部材１８として構成されている。しかしながらこれに限らず例えば、波長変換フィルタは、封止部材１８とは別に設けられてもよい。具体的に説明すると、波長変換フィルタは、太陽電池セル１０の受光面１２と、第１封止部材１８ａとの間に配置されてもよい。また、波長変換フィルタは、太陽電池セル１０の裏面１４と、第２封止部材１８ｂとの間に配置されてもよい。また、波長変換フィルタは、第１保護部材２０ａの受光側に貼り付けられてもよい。また、波長変換フィルタは、第１保護部材２０ａと第１封止部材１８ａとの間に配置されてもよい。また、波長変換フィルタは、第２保護部材２０ｂと第２封止部材１８ｂとの間に配置されてもよい。本変形例によれば、構成の自由度を向上できる。 In the embodiment of the present invention, the wavelength conversion filter in which the phosphor 30 and the scattering material 32 are mixed with the transparent resin 34 is configured as the sealing member 18. However, the present invention is not limited thereto, and for example, the wavelength conversion filter may be provided separately from the sealing member 18. If demonstrating it concretely, the wavelength conversion filter may be arrange | positioned between the light-receiving surface 12 of the photovoltaic cell 10, and the 1st sealing member 18a. The wavelength conversion filter may be disposed between the back surface 14 of the solar battery cell 10 and the second sealing member 18b. The wavelength conversion filter may be attached to the light receiving side of the first protective member 20a. The wavelength conversion filter may be disposed between the first protective member 20a and the first sealing member 18a. The wavelength conversion filter may be disposed between the second protective member 20b and the second sealing member 18b. According to this modification, the degree of freedom of configuration can be improved.
　１０　太陽電池セル、　１２　受光面、　１４　裏面、　１６　タブ線、　１８　封止部材（波長変換フィルタ）、　２０　保護部材、　３０　蛍光体、　３２　散乱材、　３４　透明樹脂、　１００　太陽電池モジュール。 10 solar cells, 12 light receiving surface, 14 back surface, 16 tab line, 18 sealing member (wavelength conversion filter), 20 protective member, 30 phosphor, 32 scattering material, 34 transparent resin, 100 solar cell module.
　本発明によれば、利用不可能な波長の光を利用可能な波長の光へ変換させながらも、透過率の低下を抑制できる。 According to the present invention, it is possible to suppress a decrease in transmittance while converting light having an unusable wavelength into light having a usable wavelength.

Claims (5)

  1. 　透明樹脂と、
    　前記透明樹脂に混合された蛍光体と、
    　前記透明樹脂に混合され、前記蛍光体の発光波長の光よりも、前記蛍光体の励起波長の光を散乱させる散乱材と、
    　を含むことを特徴とする波長変換フィルタ。     Transparent resin,
    A phosphor mixed with the transparent resin;
    A scattering material that is mixed in the transparent resin and scatters light having an excitation wavelength of the phosphor rather than light having an emission wavelength of the phosphor,
    The wavelength conversion filter characterized by including.
  2. 　前記散乱材は、５００ｎｍ以下の波長の光を散乱させることを特徴とする請求項１に記載の波長変換フィルタ。 The wavelength conversion filter according to claim 1, wherein the scattering material scatters light having a wavelength of 500 nm or less.
  3. 　前記散乱材は、粒形状を有しており、粒径の平均が５００ｎｍ以下であることを特徴とする請求項１または２に記載の波長変換フィルタ。 3. The wavelength conversion filter according to claim 1, wherein the scattering material has a particle shape, and an average particle size is 500 nm or less.
  4. 　前記散乱材の添加量は、前記散乱材の屈折率と前記透明樹脂の屈折率との差が小さいほど増やされることを特徴とする請求項１から３のいずれかに記載の波長変換フィルタ。 4. The wavelength conversion filter according to claim 1, wherein the amount of the scattering material added is increased as the difference between the refractive index of the scattering material and the refractive index of the transparent resin is smaller.
  5. 　保護部材、封止部材、太陽電池セルが積層された太陽電池モジュールであって、
    　前記封止部材は、
    　透明樹脂と、
    　前記透明樹脂に混合された蛍光体と、
    　前記透明樹脂に混合され、前記蛍光体の発光波長の光よりも、前記蛍光体の励起波長の光を散乱させる散乱材と、
    　を含むことを特徴とする太陽電池モジュール。     A solar cell module in which a protective member, a sealing member, and solar cells are stacked,
    The sealing member is
    Transparent resin,
    A phosphor mixed with the transparent resin;
    A scattering material that is mixed in the transparent resin and scatters light having an excitation wavelength of the phosphor rather than light having an emission wavelength of the phosphor,
    A solar cell module comprising:
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